Associations and interactions
between species of organisms are phenomena shared by all living things.
What varies is the extent to which the more long-lasting interactions are
beneficial or destructive to a given species and the degree of intimacy
and reliance which one organism may have developed in association with
another. Many of the more highly evolved relationships that have been studied
involve microorganisms, either in consort with other microorganisms or
with so-called higher forms of life. Mycologists are rarely surprised—but
often fascinated—by the variety of kinds of living substrates and specialized
organismal relationships that evolutionary processes have produced among
the fungi. The present book deals in some detail with the specialized dependence
of a unique group of fungi, the trichomycetes, upon certain arthropods.
There has been no comprehensive and worldwide treatment of the trichomycetes since their discovery by Joseph Leidy in 1848. The literature is scattered and in several languages, and many articles are now not only a bit old but out of date as well. As in many areas of biology, our knowledge about trichomycetes has increased somewhat exponentially in recent years. That is not to say that the time has arrived when the definitive monograph can be written, for there is much about the biology and evolution of these gut fungi and their arthropod hosts that cannot be known at present. One of my hopes, in truth, is that this book will encourage more biologists to search for the intriguing answers yet to be revealed. I have attempted to make the present monograph sufficiently self-contained and useful so as to be a firm and reliable foundation upon which to build new knowledge without an excessive need to go to the primary literature.
The monograph is divided into two major sections, one covering the various known biological aspects of the trichomycetes and their hosts, the other one being a systematic treatment of the fungi. I have tried to bring together in one book all pertinent published information on trichomycetes, and therefore it summarizes the research efforts of many biologists. Nevertheless, included are many original observations, opinions, data, and taxonomic information that have not previously appeared in print. Although no new taxa are to be found in this treatise, I have in some cases altered or emended description of species, or extended the geographic range and kinds of hosts infested by the fungi, on the basis of unpublished data.
One of the most time-consuming efforts on my part has been the sorting out of the good species from the invalid, illegitimate, or questionable ones. More named species have been discarded for these reasons than have been accepted. I have had the opportunity to examine living material, collected by myself or with collaborators, of more than half of the species recognized in the formal taxonomic treatment in Chapter 11. I have made only limited use of type specimens for two reasons. One is that designated types of valid species prior to 1958 are nonexistent. The other reason is that where types do exist, and are available, they usually consist of preserved slides which, in most cases, have little value in resolving particular taxonomic problems such as the kind outlined in Chapter 10. Mlle. Manier kindly made available during my visits to her laboratory a few slides or unpublished photographs of some species of trichomycetes about which I had some question. Throughout this book I have used the word trichomycetes, with a lower case t, when referring to the gut fungi as a biological group. This seems preferable in view of the possibility that the class Trichomycetes is polyphyletic and therefore would be considered by some as a convenient, but not a natural, grouping of fungi.
This monograph culminates many enjoyable years of research on trichomycetes conducted both in the field and the laboratory and made even more stimulating by the active contributions of various collaborators and graduate students. To all of them, whom I acknowledge in various parts of this book, I am most grateful. In particular, I would like to mention the following persons with whom I have had many lively discussions about trichomycetes: J.-F. Manier, S.T. Moss, H.C. Whisler, Y. Kobayasi, H. Indoh, and M.C. Williams. The fieldwork undertaken while away from my university in most cases has required access to nearby laboratory facilities for doing dissections of living specimens, microscopy, culture work, EM preparations, and the like. Persons at numerous field stations and other institutions in the United States and abroad kindly provided the necessary facilities, and are acknowledged in my separate publications. As well, I wish to call attention to the many biologists who have identified arthropods (an often tedious and sometimes impossible task with some larval forms); they, likewise, have been named and acknowledged in my publications.
The research which led to the present monograph was in large part supported over many years by the National Science Foundation (current grant no. BSR-8019724). The monograph could not have been written, and would not have been attempted, without the background of experience that NSF made possible. Also, a number of my graduate students who contributed materially to our knowledge of trichomycetes have had direct or indirect support from NSF. My sincere appreciation goes to this fine organization and its dedicated personnel and advisors. Of course, any opinions, findings, and conclusions or recommendations expressed in this publication are mine and do not necessarily reflect the views of the National Science Foundation.
November 1985 Robert W. Lichtwardt